Dynamics of Coherent Anharmonic Phonons in Bismuth Using High Density Photoexcitation

Muneaki Hase; Masahiro Kitajima; Shin-ichi Nakashima; Kohji Mizoguchi

doi:10.1103/PhysRevLett.88.067401

Dynamics of Coherent Anharmonic Phonons in Bismuth Using High Density Photoexcitation

Muneaki Hase, Masahiro Kitajima, Shin-ichi Nakashima, and Kohji Mizoguchi

Phys. Rev. Lett. 88, 067401 – Published 24 January 2002

Abstract

We have investigated the dynamical properties of the coherent anharmonic phonons generated in Bi under high density excitation. The time-resolved reflectivity in the intensely photoexcited Bi film is modulated by the coherent $A_{1 g}$ phonon oscillation with a time-dependent oscillation period. As the pump power density is increased, the line shape of the $A_{1 g}$ mode in the Fourier transformed spectra becomes asymmetric, and the redshift of the phonon frequency is observed. Analysis of the transient redshift with a wavelet transform reveals that the frequency of the $A_{1 g}$ mode depends on the squared amplitude of the oscillation, which is attributed to an anharmonicity of the lattice potential.

Received 27 August 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.067401

Authors & Affiliations

Muneaki Hase^1,*, Masahiro Kitajima¹, Shin-ichi Nakashima², and Kohji Mizoguchi³

¹Materials Engineering Laboratory, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
²Power Electronic Research Center, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8561, Japan
³Department of Applied Physics, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan